Over the years, many different types of electronic message transmission devices have been developed. For transmitting spoken messages, one of the oldest, most widely used and convenient of these devices is the telephone. However, until quite recently, the telephone provided only live, real-time communication. Recently, "voice mail" services have become available that permit callers to leave spoken messages for later retrieval and reproduction to their intended recipients. While convenient, the cost of transmitting voice messages over the public phone system is relatively high in comparison with the cost of transmitting messages using surplus capacity that is available in communication systems that have been installed and are maintained in continuous operation for entirely different purposes.
Another recently developed message transmission technology is one with the ability to transmit text messages for later retrieval and reproduction by their intended recipient. Such systems are known as electronic mail and utilize an underlying technology known as a "Store And Forward Message Switch". However, most current electronic mail systems are both expensive and must be accessed using special purpose terminals. Presently, there exists no widely available means by which the public can conveniently and inexpensively access electronic mail communication.
Yet other recently developed communication systems are the many independently operated ATM systems and POS systems. One of the characteristics of the various ATM and POS systems is their interconnection by many clearing house networks. These clearing house networks pass transactions back and forth between terminals on one ATM or POS system and another ATM or POS system on which the user's account identification records reside.
It appears desirable to link parts of existing communication systems to provide readily accessible public electronic mail communication that frees users from the need to use a special purpose terminal. Such a combined system facilitates sending and receiving electronic mail and also provides much greater functionality to the existing voice and data communication systems.